“Atheists can’t understand it because they refuse to experience it.”
Well, let’s not say they all can’t understand. I understand it now, and I was in their position not too long ago. They don’t understand, but they certainly can, if they open themselves to God’s message.
I went through a period of being an atheist, actually. I didn’t like it very much. Eventually I reached the conclusion that it just wasn’t real. I couldn’t do it anymore.